Identification of Bacterial DNA in the Peripheral Blood of Patients With Active Psoriasis | Dermatology | JAMA Dermatology | JAMA Network
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Research Letter
June 2015

Identification of Bacterial DNA in the Peripheral Blood of Patients With Active Psoriasis

Author Affiliations
  • 1Department of Dermatology, Centro Dermatológico Estético, Alicante, Spain
  • 2Clinical Research Unit, Centro Dermatológico Estético, Alicante, Spain
  • 3Infectious Diseases Unit, Centro Dermatológico Estético, Alicante, Spain
  • 4Department of Clinical Medicine, Miguel Hernández University, Elche, Alicante, Spain
  • 5Centro de Investigación Biomédica en Red, Enfermedades Hepáticas y Digestivas, Instituto de Salud Carlos III, Madrid, Spain
  • 6Digestive Disease Institute, Cleveland Clinic Abu Dhabi, Abu Dhabi, United Arab Emirates
  • 7Department of Pharmacology, Pediatrics and Organic Chemistry, Miguel Hernández University, Elche, Alicante, Spain
JAMA Dermatol. 2015;151(6):670-671. doi:10.1001/jamadermatol.2014.5585

Psoriasis is a systemic autoimmune inflammatory disease that shares some immunological aspects with other inflammatory-based diseases, such as Crohn disease.1 Bacterial DNA (bactDNA) fragments have been shown to induce a systemic immunological response in Crohn disease and other settings.2,3 Although the results of most blood bacterial cultures are negative in patients with psoriasis, we hypothesized that the presence of bactDNA in the blood might act as a molecular trigger in disease outbreaks and induce a systemic inflammatory response in these patients.

This study included a consecutive series of patients whose psoriasis had previously cleared or was being controlled exclusively with topical medications who had a new flare of psoriasis and a group of sex- and age-matched control participants without psoriasis. The study protocol was approved by the Research Ethics Committee of the Hospital General Universitario de Alicante and all patients gave written informed consent. Exclusion criteria were the use of systemic corticosteroids, methotrexate sodium, cyclosporine, or anti–tumor necrosis factor drugs in the previous 3 months, antibiotic use in the previous 2 weeks, and the concomitant diagnosis of cirrhosis, intestinal bowel disease, and signs of bacterial infection. At the time of inclusion, patients were classified into severe, severe to moderate, moderate, or slight psoriasis, according to the international Psoriasis Area Severity Index.